The present invention relates generally to air treatment systems, such as room air purifiers. More particularly, it relates to mechanisms for retaining a removable filter within a portable air treatment device housing, and methods of inserting a filter into, and removing the filter from, a portable air treatment device housing.
Various portable air treatment systems are available for use in filtering or otherwise treating air in closed environments. These air treatment systems can assume a variety of forms, and generally include a housing maintaining a blower or fan, along with a filter. The blower directs room air through the filter to remove various contaminants, such as particles, dust, pollen, odors, etc. The treated air is then directed back into the environment in which the system is located. The system may be designed to perform other functions (e.g., a dehumidifier), but typically provides a user with the ability to remove and replace the filter. With this approach, then, regardless of an exact form of the filter (e.g., HEPA filters, multi-layered filters, pleated filters, etc.), upon partial or full saturation or loading of the filter with room air contaminants, the used filter is simply replaced with a new filter, thus extending an overall useful life of the air treatment system. This cost effective approach is highly desired by consumers.
In light of the above consumer expectations, efforts have been made to devise mechanisms for retaining an otherwise removable filter within the air treatment device's housing. Ease of consumer handling is normally a desired attribute, along with ensuring that once assembled within the housing, the filter will not easily be displaced. Most filters useful with portable air treatment systems are relatively flat. As such, where the air treatment device is designed such that the filter is maintained horizontally, mechanisms for releasably retaining the filter can be fairly simplistic. For example, a horizontally-oriented filter loaded through a top of the unit's housing can simply be placed against a flat surface, with gravity acting to keep the filter in place. However, this orientation may not be conducive to a compact overall design capable of achieving a desired incoming/outgoing airflow pattern, and thus many portable air treatment systems position the filter in an upright or nearly upright fashion.
For upright (or nearly upright) applications, a more robust retaining mechanism capable of capturing the filter is a virtual requirement. For example, where a movable panel or door is the only structure holding the filter in place, once the panel/door is opened, the filter may naturally fall out of the housing. If the filter is loaded or saturated with contaminants/particles, this occurrence is highly undesirable as the contaminated filter will fall on to the user's floor, in turn causing particles retained by the filter to become dislodged and soil the contacted surface. As a result, various, oftentimes complex, retaining mechanisms for upright (or nearly upright) filters orientations have been suggested. These include, for example, metal or plastic springs, rotating latches or catches, etc. While these mechanical solutions are viable, they may entail certain long term complications (e.g., a movable latch acts as a lever and typically concentrates stresses at the base thereof, perhaps leading to failure with repeated use), and represent an added expense. Conversely, the system may be configured to rely upon a solid friction fit or a moveable friction fit between the filter and the housing. A solid friction fit (e.g., a cardboard-framed filter in a solid plastic housing opening) requires that the filter be manufactured to a very tight size tolerance; this, in turn, increases costs and may not be consistently achieved. Similarly, the moveable friction fit approach (e.g., a foam or rubber gasket that is applied to and/or moves with a perimeter of the filter) is again characterized by additional parts and/or expense. Additionally, the frictional fit may interfere with achieving a desired air seal against the filter frame during use.
Current techniques for removably retaining a filter within a portable air treatment system housing are less than optimal. Therefore, a need exists for filter retaining mechanisms that are inexpensive, easy to manufacture, and easy to use.